Mice receiving Sotuletinib hydrochloride or a vehicle are monitored for symptom-free survival, with the vehicle group showing a median survival of 5-7 weeks. Remarkably, Sotuletinib hydrochloride markedly extends long-term survival, with 64.3% of subjects alive at the 26-week trial conclusion, a duration chosen due to spontaneous tumor development in Ink4a/Arf / mice around ~30 weeks. Sotuletinib hydrochloride demonstrates a high tolerance in prolonged treatment without noticeable side effects, aligning with histopathological findings. Histological analysis shows all vehicle-treated mice developed high-grade, invasive gliomas, whereas Sotuletinib hydrochloride treatment results in significantly less malignant tumors, with 55.6% of asymptomatic mice showing no detectable lesions at the trial's end^[1].

Mice treated with Sotuletinib hydrochloride exhibit decreased CSF1R staining in cervical tumors and their surrounding stroma, demonstrating a notable reduction in CSF1R⁺ stromal macrophages compared to those treated with the vehicle (P<0.05)^[2].

Sotuletinib hydrochloride suppresses CSF-1-induced proliferation (EC50=67 nM) in bone marrow-derived macrophages (BMDMs) and reduces CSF-1R phosphorylation, akin to CSF-1R antibody inhibition. It also lowers the viability of CRL-2467 microglia, Ink4a/Arf / BMDMs (PDG genetic background), and NOD/SCID BMDMs. Notably, in vitro treatment with Sotuletinib hydrochloride does not influence the proliferation of PDG-derived tumor cell lines (all Csf-1r-negative), U-87 MG human glioma cells, or affect PDG cell tumor sphere formation. Therefore, Sotuletinib hydrochloride directly targets macrophage survival via CSF-1R blockade without impacting glioma cells^[1].